Angular alignment error measuring system

ABSTRACT

Collimated light is directed to a mirror mounted on a missile gimbal system and to a mirror mounted on a navigation optical reference. Any angular deviation from the ideal missile alignment results in light reflected from the mirrors non-parallel to the directed light. The angular variation is detected by a sensor in the collimator and the light beam is deviated by a wedge drive unit until the light is normal to the reflector. An electrical signal is generated proportional to the light beam angular compensation, to realign the missile. This invention is an improvement to the previously used angular alignment system; the improvement comprising fixed azimuth error indicator station assemblies, one station assembly mounted between each pair of missiles in a longitudinal or series array of missiles within the submarine. Each station assembly has a pair of reflectors assembled as a pentamirror, directing the collimated light to either the port or starboard missiles, or the pentamirror can be arranged to pass the light through to the next successive station, and each station assembly has a pair of wedge drive assemblies to deviate the light and measure the missile bearing misalignment angle of the port and starboard missiles.

Unite States Patent 1 Degnan et al.

[ 1 Jan. 9, 1973 [54] ANGULAR ALIGNMENT ERROR MEASURING SYSTEMInventors: William J. Degan, Richard W.

Samsel, both 'of Pittsfield, Mass.

represented by the Secretary of the Navy Filed:

Primary Examiner-Samuel Feinberg Assistant Examiner-S. C. BuczinskiAtt0rney-R. S. Sciascia and Q. E. Hodges PHOTOELECTRIC AUTOCOLLIMATORAssignee: The United States 'br'ifiier ic' as [57] ABSTRACT Collimatedlight is directed to a mirror mounted on a missile gimbal system and toa mirror mounted on a navigation optical reference. Any angulardeviation from the ideal missile alignment results in light reflectedfrom the mirrors non-parallel to the directed light. The angularvariation is detected by a sensor in the collimator and the light beamis deviated by a wedge drive unit until the light is normal to thereflector. An electrical signal is generated proportional to the lightbeam angular compensation, to realign the missile. This invention is animprovement to the previously used angular alignment system; theimprovement comprising fixed azimuth error indicator station assemblies,one station assembly mounted between each pair of missiles in alongitudinal or series array of missiles within the submarine. Eachstation assembly has a pair of reflectors assembled as a pentamirror,directing the collimated light to either the port or starboard missiles,or the pentamirror can be arranged to pass the light through to the nextsuccessive station, and each station assembly has a pair of wedge driveassemblies to deviate the light and measure the missile bearingmisalignment angle of the port and starboard missiles.

6 Claims, 8 Drawing Figures STARBOARD 46 /AUTOCOLLI MATOR PATENTEDJAH 9ms 3 7'09 .608

sum 2 OF 4 Fan mNL M mm @M mmv v m VGM W5 A a wt w m a. W.R.

PATENTEDJAN 9 ms SHEET 3 OF 4 INVENTORS W. J. DEG/VAN y R. H. SAMSELATTORNEY PAIENTEDJAII 91973 3.709.608

SHEU l 0F 4 67 rGEAR TRAIN INVENTORS W. J. DEGNAN B R. W. SAMSELATTORNEY ANGULAR ALIGNMENT ERROR MEASURING SYSTEM BACKGROUND AND SUMMARYOF THE INVENTION The present invention relates to an improvement to anangular alignment error measuring system generally described in U.S.Pat. No. 3,326,076. The device of U.S. Pat. No. 3,326,076 comprises asource of collimated light directed through a mirror system to a prismmounted on the missile gimbal axis. Misalignment error of the missile ismanifest as an angular deviation between the reflected light and thedirected light. An azimuth error indicator station assembly, denoted bynumber 22 in the U.S. Pat. No. 3,326,076 comprises a wedge driveassembly and a system of pentamirrors for controlling the path of thelight. The wedge drive assembly resolves the angular difference betweenthe directed and reflected light and transmits an appropriate electricalerror signal to the missile servo system. The directed light is alignedwith the ship's inertial navigational system (denoted by number 15 inU.S. Pat. No. 3,326,076).

In this improvement the azimuth error indicator station assemblycorresponding to numeral 22 in U.S. Pat. No. 3,326,076, is not mountedfor movement, but one azimuth error indicator station assembly isstatically mounted between each pair of missiles in a longitudinalmissile series array. The improvement, comprising fixed stationassemblies makes this a fixed optic system as compared to the movingtrolley system of U.S. Pat. No. 3,326,076 device and is a simple, morereliable and faster performing system.

Accordingly, one object of this invention is a fixed optic angularalignment error measuring system.

A second object of this invention is a simpler, more reliable and fasterperforming angular alignment error measuring system.

These and other objects of the invention will be better understood whenthe following description of the invention is read.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 shows a plan view of theangular alignment error measuring system.

FIG. 2a shows a portion of the system shown in FIG. 1, arranged tooperate with a casualty to the starboard photoelectric autocollimator.

FIG. 2b shows a portion of the system shown in FIG. 1, arranged tooperate with a casualty to the port photo-electric autocollimator.

FIG. 3a shows a portion of the system of FIG. 1, arranged to align theport side photoelectric autocollimator with the ORU.

FIG. 3b shows a portion of the system shown in FIG. 1, arranged to alignthe starboard side photoelectric autocollimator to the ORU.

FIG. 4 shows the pentamirror and its control system with the pentamirrorarranged in its see through position wherein light is passed throughbetween the pentamirror surfaces.

FIGS. 5a and 5b shows the pentamirrors arranged to change the directionof the light path +90 and 90, respectively.

DESCRIPTION OF THE PREFERRED EMBODIMENT Referring now to FIG. 1, a planview of the angular alignment error measuring system used in a missilearray is shown. The typical missile array shown comprises eightmissiles. Missiles numbered 11, 12, 13 and 14 are arrayed on the portside of the ship with respect to the ships centerline 10 and missiles11', 12', 13' and 14 are arrayed on the starboard side of centerline l0.Missiles l1 and 11', 12 and l2, l3 and 13 and 14 and 14', are designatedmissile pairs, which are arrayed to be opposite each other in theathwartship direction and are separated by the centerline of the ship.Each of the missile pairs, 11-11, 12-12, 13-13 and 14 14, has associatedwith it. an azimuth error indicator station assembly denoted by numerals21, 22, 23 and 24, respectively. Station assemblies 21 and 22 are shownlocated on the starboard side of centerline 10 while station assemblies23 and 24 are shown located on the port side of the centerline; stationassemblies 21 and 22 are in series and in line and connected by lighttube 31 and station assemblies 23 and 24 in series and in line andconnected by light tube 33.

The azimuth error indicators (station assemblies) are substantially asdescribed in U.S. Pat. No. 3,326,076, including pentamirror surfaces tocontrol the light path through the azimuth error indicator. In addition,each station assembly wedge drive unit comprises a pair of optical wedgesets, each set being the contra-rotating optical wedges 36 and 37, shownas part of the wedge drive unit in U.S. Pat. No. 3,326,076. As shown inFIG. 1, wedge sets 2la and 21b are associated with station assembly 21,wedge sets 22a and 22b are associated with station assembly 22, andwedge sets 23a and 23b are associated with station assembly 23, andwedge sets 24a and 24b are associated with station assembly 24. Eachwedge set within a station assembly faces and is used in conjunctionwith the porroprism 35 of its respective facing missile (i.e., 21a withmissile 11' and 21b with missile 11).

Each of the missiles 11-14 and l1'-14, is represented orientationally bya porroprism. When a missile is angularly misaligned in azimuth, themissile porroprism 35 is similarly misaligned.

A photoelectric autocollimator table assembly 40 is rigidly bolted to aships bulkhead. Three adjustable photoelectric autocollimators 42, 44and 46 are mounted on the photoelectric autocollimator table assembly 40and all are aligned parallel to each other and aligned with the ship'sinertial navigation system. Mounted on the photoelectric autocollimatortable assembly are three servo amplifier assemblies (not shown), twotable pentamirror assemblies 52 and 50 and one station assembly 48. Analignment periscope 54 is arranged opposite reference station 48 and isstructured to direct the beam of light from photoelectricautocollimators 42, 44 or 46, to the optical reference unit 56 as willbe hereinafter described.

OPERATION OF THE DEVICE As shown in FIG. 1, the photoelectricautocollimator 42 directs the beam of collimated light a, to stationassembly 48. Pentamirror 48a, within station assembly 48, changes thedirection of light beam a and directs it through periscope 54 to theoptical reference unit 56. The optical reference unit 56 reflects alight beam b, through periscope 54 to pentamirror 48a, which changes itsdirection and directs reflected beam b back towards photoelectricautocollimator 42 and through wedge drive assembly 48b.

Similarly, as shown in FIG. 1, photoelectric autocollimator 44 directsits beam of light 0, to a pentamirror 50 which changes its direction anddirects it through light tube 31 to station assembly 21. The pentamirrorwithin station assembly 21 is arranged in the pass through position andthe light beam 0, is thereby passed through station assembly 21 tostation assembly 22, in series with station assembly 21. The pentamirrorwithin station assembly 22 is arranged to direct the beam of light toporroprism 35, associated with missile 12'. Light beam d, reflected fromthe prism 35 is directed back through station assembly 22, passingthrough wedge unit 22a within station assembly 22.

Similarly, as shown in FIG. 1, photoelectric autocollimator 46 directsthe beam of light e, through pentamirror 52 which changes its directionto pass through the light tube 33 to station assembly 23. Thepentamirror within station assembly 23 is arranged in the pass throughposition whereby light is passed through to station assembly 24. Thepentamirror within station assembly 24 is arranged to deflect the lightto porroprism 35 attached to missile 14. The prism reflects beam f, backtowards station assembly 23, where it passes through the wedge unit 24a.

The photoelectric autocollimator light beam defines the alignment firecontrol line of site reference axis normally parallel to the shipscenterline 10. The optical reference unit axis is established bynavigation from known angular relation to the ships inertial navigationsystem. The light paths from the photoelectric autocollimators 44 and 46to any of the missile prisms 35 is used to detect deviations in missileazimuth alignment. The light path from the photoelectric autocollimator42, to the optical reference unit detects any angular deviation betweenthe optical reference unit and the reference photoelectricautocollimator that may be induced by ship flexure. The anglemisalignment signals produced by the light path to the optical referenceunit is combined with the angle misalignment signal produced in a lightpath to any one missile and the combined angular deviation is themisalignment angle from the missile.

Referring now to FIG. 4, the pentamirror and the associated pentamirrorcontrol system is shown. Each pentamirror assembly consists of twomirrors 63 and 64, mounted on a rotating table 60. The mirrors aremounted with the reflecting surfaces 63a and 64a perpendicular to thetable surface and facing each other. The mirrors are positioned relativeto each other so that by rotating the table 60, light beam K enteringthe pentamirror assembly may be passed through without effecting itsdirection or the light beam may be redirected +90 or 90 from itsentering path K as shown by light beam K in FIG. 4a and light beam K inFIG. 4b. Table 60 is attached through gear train 67 to motor 66. Motor66 is responsive to a signal from the pentamirror control system 65 andupon the appropriate command will position the pentamirror table to passthe light beam through the pentamirror or direct it i from its incomingpath direction to the selected missile.

Referring to FIG. 1, wherein the system is shown, it is seen that eachstation assembly has two wedge sets, i.e., wedge sets 21a and 21b withinstation assembly 21. The control over the light path through a stationassembly is maintained by positioning of the pentamirrors within each ofthe station assemblies 21-24. The pentamirrors in each station assembly,although shown in one position in FIG. 1, may be changed in position topass light through a station assembly, reflect light to its associatedport missile or to its associated starboard missile. In the case ofstation assembly 21, the pentamirrors within this station assembly maybe arranged to pass light through wedge set 21a to missile 11 or may berotated to a second position as shown in FIG. 5b, to pass light throughwedge set 21b to missile 11. By properly positioning each of thepentamirrors within the station assemblies, the misalignment angle ofeach missile of a missile pair may be separately measured by itsrespective station assembly.

The angle misalignment is sensed by the wedge drive assembly within astation assembly and converted to an electrical signal which causes themissile servo system to correct for any angular misalignment immediatelyprior to firing the missile. The servo optical resolver system is asdescribed in U.S. Pat. No. 3,326,076.

Referring now to FIGS. 2a and 2b, the operation of the angularmisalignment system is shown where a casualty is suffered by either thestarboard photoelectric autocollimator 44 or the port photoelectricautocollimator 46. As shown in FIG. 2a, where the starboard sidephotoelectric autocollimator 44 cannot be used, the pentamirror 52 canbe rotated to its see through position passing the beam of light fromphotoelectric autocollimator 46 to pentamirror 50. Pentamirror 50 ispositioned to direct light from the collimator 46 through to light tube31 and the station assemblies connected by light tube 31.

As shown in FIG. 2b, when a casualty is suffered by the port sidephotoelectric autocollimator pentamirror 50 may be rotated to its seethrough position so that the beam of light from photoelectricautocollimator 44 may be passed through to pentamirror 52. Pentamirror52 is positioned to direct its beam of light to light tube 33 and thestation assemblies associated therewith.

Referring to FIGS. 3a and 3b, it is shown how each of the photoelectricautocollimators 44 and 46 may be separately aligned with the opticalreference unit 56. As shown in FIG. 3a, pentamirror 52 is positioned todirect the beam of light from photoelectric autocollimator through topentamirror 48. Pentamirror 48 is rotated to pass the beam of light fromphotoelectric autocollimator 46 through periscope 54 to ORU 56. In FIG.3b, the light beam from photoelectric autocollimator 44 is directedthrough pentamirror 50 which is positioned to pass the beam of lightthrough it to pentamirror 52. Pentamirror 52 is positioned to direct thebeam of light from photoelectric autocollimator 44 through topentamirror 48, pentamirror 48 being positioned to pass its beam oflight through to periscope 54 and on to ORU 56.

Where the optical light path is excessive in length, additionalcollimators can be placed within the system. For example, thephotoelectric autocollimator 42,

directing a beam of light towards the optical reference unit can bestatically aligned to a second photoelectric autocollimator through theuse of a two side test mirror or any other suitable device which is thenremoved when the alignment is completed.

Obviously many modifications and variations of the present invention arepossible in the light of the above teachings. It is therefore to beunderstood that within the scope of the appended claims the inventionmay be practiced otherwise than as specifically described.

What is claimed is:

1. In an angular alignment error measuring system for determining theangular misalignment between a missile in an array and the navigationalsystem of a ship;

the measuring system having an optical reference unit aligned with theships centerline;

a missile array with missile pairs of said array being positionedopposite each other in the athwart ship direction and separated by thecenterline of the ship;

a porro-prism mounted on each missile;

each said missiles orientation being represented by the orientation ofits respective porro-prism;

first and second photoelectric autocollimating means disposed betweenthe missile array and the optical reference unit;

the first photoelectric autocollimating means providing and projecting afirst collimated light beam to the optical reference unit;

said first photoelectric autocollimating means receiving the light beamreflected by said optical reference unit and providing a first errorsignal indicative of the angular position of the first photoelectricautocollimating means with respect to the optical reference unit;

the second photoelectric autocollimating means optically aligned withthe first autocollimating means, generating a second collimated lightbeam optically parallel with the first light beam;

station assemblies transferring the second light beam to the missileporro-prism and transferring the reflected light beam from said missileporro-prism to the second photoelectric autocollimating means;

the second photoelectric autocollimating means receiving the reflectedlight beam and providing a second electrical error signal continuouslyindicative of the angular position of a missile within said array withrespect to the ships centerline;

the station assemblies additionally including a pentamirror fortransferring the light beams between the photoelectric autocollimatingmeans and the porro-prism;

wherein the comprises improvement statically mounted series alignedstation assemblies; and

the series alignment being parallel to the length of the missile arraywith a single station assembly aligned with each missile pair, in theathwartship direction.

2. The system of claim 1 wherein each of said station assembly containsa pentamirror assembly, said pentamirror assembly being rotatable aboutan axis passing between the reflecting surfaces of said pentamirrorassembly whereby a beam of li h t may be changed in direction plus orminus an directed to each missile in said missile pair or the beam maybe passed through a station assembly between the pentamirror surfaces tothe next succeeding station assembly in the array.

3. The system of claim 2 wherein the series station assemblies areconnected by a light confining means;

and

said light confining means is a light tube to limit thermal disturbancesin the light beam.

4. The system of claim 1 including:

a third photoelectric autocollimating means optically aligned with thefirst autocollimating means, generating a third collimated beam oflight, directed optically parallel with the first light beam, anddirected to said station assemblies;

said station assemblies including a first and second set of seriesaligned station assemblies;

said second photoelectric autocollimator being aligned with said firstset of series aligned station assemblies;

said third photoelectric autocollimator being aligned with said secondset of series aligned station assemblies.

5. The system of claim 4, including:

means to direct a beam of light from said second photoelectricautocollimator to said second set of station assemblies for detectingthe misalignment angle of a missile aligned with said second set ofstation assemblies; and

means to direct a beam of light from said third photoelectricautocollimator to said first set of station assemblies for detecting amisalignment angle of a missile aligned with said first set of stationassemblies.

6. The system of claim 5 including:

means to direct a beam of light from said second photoelectricautocollimator to said first set of station assemblies for detecting themisalignment angle of a missile aligned with said second set of stationassemblies; and

means to direct a beam of light from said third photoelectricautocollimator to said second set of station assemblies for detecting amisalignment angle of a missile aligned with said first set of stationassemblies.

1. In an angular alignment error measuring system for determining theangular misalignment between a missile in an array and the navigationalsystem of a ship; the measuring system having an optical reference unitaligned with the ship''s centerline; a missile array with missile pairsof said array being positioned opposite each other in The athwart shipdirection and separated by the centerline of the ship; a porro-prismmounted on each missile; each said missile''s orientation beingrepresented by the orientation of its respective porro-prism; first andsecond photoelectric autocollimating means disposed between the missilearray and the optical reference unit; the first photoelectricautocollimating means providing and projecting a first collimated lightbeam to the optical reference unit; said first photoelectricautocollimating means receiving the light beam reflected by said opticalreference unit and providing a first error signal indicative of theangular position of the first photoelectric autocollimating means withrespect to the optical reference unit; the second photoelectricautocollimating means optically aligned with the first autocollimatingmeans, generating a second collimated light beam optically parallel withthe first light beam; station assemblies transferring the second lightbeam to the missile porro-prism and transferring the reflected lightbeam from said missile porro-prism to the second photoelectricautocollimating means; the second photoelectric autocollimating meansreceiving the reflected light beam and providing a second electricalerror signal continuously indicative of the angular position of amissile within said array with respect to the ship''s centerline; thestation assemblies additionally including a pentamirror for transferringthe light beams between the photoelectric autocollimating means and theporro-prism; wherein the improvement comprises statically mounted seriesaligned station assemblies; and the series alignment being parallel tothe length of the missile array with a single station assembly alignedwith each missile pair, in the athwartship direction.
 2. The system ofclaim 1 wherein each of said station assembly contains a pentamirrorassembly, said pentamirror assembly being rotatable about an axispassing between the reflecting surfaces of said pentamirror assemblywhereby a beam of light may be changed in direction plus or minus 90*and directed to each missile in said missile pair or the beam may bepassed through a station assembly between the pentamirror surfaces tothe next succeeding station assembly in the array.
 3. The system ofclaim 2 wherein the series station assemblies are connected by a lightconfining means; and said light confining means is a light tube to limitthermal disturbances in the light beam.
 4. The system of claim 1including: a third photoelectric autocollimating means optically alignedwith the first autocollimating means, generating a third collimated beamof light, directed optically parallel with the first light beam, anddirected to said station assemblies; said station assemblies including afirst and second set of series aligned station assemblies; said secondphotoelectric autocollimator being aligned with said first set of seriesaligned station assemblies; said third photoelectric autocollimatorbeing aligned with said second set of series aligned station assemblies.5. The system of claim 4, including: means to direct a beam of lightfrom said second photoelectric autocollimator to said second set ofstation assemblies for detecting the misalignment angle of a missilealigned with said second set of station assemblies; and means to directa beam of light from said third photoelectric autocollimator to saidfirst set of station assemblies for detecting a misalignment angle of amissile aligned with said first set of station assemblies.
 6. The systemof claim 5 including: means to direct a beam of light from said secondphotoelectric autocollimator to said first set of station assemblies fordetecting the misalignment angle of a missile aligned with said secondset of station assemblies; and means to direct a beam of light from saidthird photoelectric autocollimator to said second set of staTionassemblies for detecting a misalignment angle of a missile aligned withsaid first set of station assemblies.